COSMOS, VOL. II - World eBook Library

OCEANIC DISCOVERIES. 631
his Arte de naveyar, till the invention of the instrument
made by Martin Behaim in 1484 at Lisbon, and which was,
perhaps, only a simplification of the friend Regiomontanus. When the
meteoroscope of his
Infante Henry, Duke of
Yir-eo, who was himself a navigator, established an academy
for pilots at Sagres, Maestro Jayme of Majorca was named its
director. Martin Behoim received a charge from King John
II. of Portugal to compute tables for the sun's declination,
and to teach pilots
to **
navigate by
and stars." It cannot at present be decided whether, at
the close of the fifteenth century, the use of the log was
known as a means of estimating the distance traversed
whilst the direction is indicated by the compass but it is
;
the altitudes of the sun
certain that Pigafetta, the companion of Magellan, speaks of
the log (la catena a poppa), as of a well-known means of
measuring the course passed over.*
*
In all the writings on the art of navigation which I have examined,
I have found the erroneous opinion that the log for the measurement
of the distance traversed, was not used before the end of the sixteenth
or the beginning of the seventeenth century. In the Encyclopaedia
Britannica (seventh edition, 1842), vol. xiii. p. 416, it is further stated,
" The author of the device for measuring the ship's way is not known,
and no mention of it occurs till the year 1607, in an East Indian voyage
published by Purchas." This year is also named in all earlier and later
dictionaries*as the extreme limit (Gehler, bd. vi. 1831, s. 450). Navarre
te alone, in the Dissertation sobre los progresos del Arte de Navegar,
1802, places the use of the log-line in English ships in the year 1577.
(Duflot de Mofras, Notice biographique sur Mendoza et Navarrete,
1845, p. 64.) Subsequently, in another place (Coleccion de los Viages
de los Espafioles, t. iv. 1837, p. 97), he asserts that, "in Magellan's
time the speed of the ship was only estimated by the eye (a ojo),
until, in the sixteenth century, the corredera (the log) was devised."
The measurement of the distance sailed over by means of throwing the
log, although this means must, in itself, be termed imperfect, has
become of such great importance towards a knowledge of the velocity
and direction of oceanic currents, that I have been led to make it an
object of careful investigation. I here give the principal results
which are contained in the sixth (still unpublished) volume of my
Examen critique de I'histoire de la Geographic et des progres de
TAstronomic nautique. The Romans, in the time of the republic, had
in their ships way-measurers, which consisted of wheels four feet high,
provided with paddles attached to the outside of the ship, exactly as in,
our steamboats, and as in the apparatus for propelling vessels, which
Blasco de Garay had proposed, in 1543, at Barcelona to the Emperor